1 cup balsamic vinegar
1 cup ruby port
1 large vanilla bean
1/2 cup sugar
additional pure vanilla extract to taste
In a heavy, non-reactive saucepan, combine vinegar, port, and vanilla bean that is split open and seeds scraped into mixture. Add the sugar when the mixture has almost come to a boil. Bring to boil, then reduce heat and simmer sauce until thick and syrupy (about 30 minutes for a single batch). Allow to cool, add vanilla extract to taste, and bottle. You can keep the bean in the mixture or add a fresh bean. This keeps well in the refrigerator.